The wearing of safety helmets for sporting activities has become more commonplace and accepted, and also in some instances mandated by law. Many states require persons riding bicycles, particularly children, to wear an approved safety helmet. Helmets are also worn by adults when riding motorcycles, and particularly children when engaged in sporting activities such as ice skating and in-line skating in which the possibilities of an accident, and a traumatic head injury resulting from an accident, are relatively great.
Safety helmets typically comprise a helmet body made from styrofoam or another light weight, impact-absorbing substance. The helmet body is often times partially or fully covered with a harder outer shell that is commonly made of a more dense plastic material. Safety standards for such helmets have been promulgated by organizations such as the American National Standards Institute.
Many of these sporting activities can and do take place at night, particularly the riding of bicycles and motorcycles. Obviously, rider visibility is of utmost concern in these situations. Vehicle visibility can be increased by the use of reflectors and battery or generator-powered lights attached to the vehicle frame. Rider visibility may be enhanced by the use of reflective materials on shoes or other articles of clothing. There are also small battery-powered light units that can be attached to the helmet. Such lighting units, however, are primarily for lighting the ground area in front of the cyclist, and thus do not substantially increase rider visibility.